1. Field of the Invention
The present invention relates to a scroll position estimation apparatus and method used for the process of visualizing each sub-data item when a complex document, such as a web page embedded with a plurality of images, formed of main data and sub-data items is input.
2. Description of the Related Art
When visualizing (presenting) a complex document formed of main data and sub data (for example, Hypertext Markup Language [HTML] data and images embedded therein), the time required for visualizing the main data may significantly differ from that required for visualizing the sub-data. For instance, download time is regarded as a time required for visualization. A Web browser for visualizing HTML data requests downloading embedded images in the order of HTML analysis, and visualizes the images in the order of arrival. At this time, the order of presenting embedded images is not always identical to that of presentation desired by a Web page designer or user.
In light of the above, there has been proposed a method for presenting images in the order desired by a Web page designer, in which the order of downloading sub-data is designated to visualize the sub-data in the order desired by the Web page designer of HTML data (see, for example, Institute of Electronics, Information and Communication Engineers Article D-I vol. J84-D-I No. 2, pp. 155-164, 2001, “A Page Transmission Mechanism with Transmission Order Control of Inline Objects,” written by Nakano, et al.).
In the prior art, although Web page designers can control the order of visualization of sub-data, they cannot change the order of visualization in accordance with a change in user-side environment caused by, for example, a scroll operation. More specifically, there may be a case where sub-data to be skipped by a screen scroll operation is preferentially visualized, compared to sub-data to be selected by the scroll operation.
Further, when an image or Web page is displayed on a small screen such as the screen of a cellular phone or PDA, scrolling is often utilized. In the prior art, an interface is provided in which whenever a user operates a button, the scroll position of the screen is updated, thereby updating the display area. In this case, the user must operate the button whenever they need scrolling.